Shelf



FIG. 1 is a front perspective of a shelf showing our new design;

FIG. 2 is a rear perspective view of the shelf thereof;

FIG. 3 is front view of the shelf thereof;

FIG. 4 is back view of the shelf thereof;

FIG. 5 is side view of the shelf thereof;

FIG. 6 is top view of the shelf thereof; and,

FIG. 7 is bottom view of the shelf thereof. 

CLAIM The ornamental design for a shelf, as shown and described. 